Osteoarthritis is the most prevalent joint disease in the world. Some of the predisposing factors for this disorder include: age, a history of trauma and obesity. Patient complaints usually include pain, rigidity of the joints, morning stiffness and limitation of movement. To treat each patient, an individual decision needs to be made. Treatment includes non-pharmacological measures (like education sessions, exercise programs for retention of movement range and muscle strength, use of helping devices, weight control and dietary supplements), pharmacological treatments (like local and systemic analgesics) and surgical measures.
Menthol is among the active ingredients in mint and its superficial counter-irritant and local analgesic effects are entirely accepted. When mint essential oil or menthol is rubbed in the skin, they simultaneously stimulate the nerves responsible for sensation of cold and block the nerves responsible for sensual perception of pain.
Based on the results of studies carried out in animals, menthol exerts its analgesic effects through activation of endogenous opioid system and to some extent through its local anesthetic properties without having anti-inflammatory effects. Also, mint essential oil inhibits muscular contractions induced by serotonin and substance P.
Based on the results of studies carried out in animals, celery essential oil has anti-inflammatory, anti-spasmodic and relaxant properties. Mint essential oil has anti-inflammatory and anti-spasmodic properties.
In a study to evaluate the analgesic and anti-inflammatory properties of celery essential oil and the combination of these two essential oils in rat and mice, it was demonstrated that in carrageenan test, mint essential oil, celery essential oil and the combination of these essential oils have considerable local anti-inflammatory effects. Mint essential oil and the combination of mint and celery essential oils significantly inhibited the pain in the first phase of formalin test, which is a neurogenic pain and is caused by direct stimulation of pain nerves. Also, mint essential oil and the combination of mint and celery essential oils had significant inhibitory effect on phase 2 pain on the formalin test, which is an inflammatory pain.
In a placebo-controlled, double-blind study, 102 patients with knee osteoarthritis were randomly divided into three groups: mint lotion, min-celery lotion (CM Topical Lotion) and placebo lotion, to use the lotion locally 2 times per day. Re-examination was done 1, 2, 3 and 4 weeks after the initial examination and the intensity of pain were evaluated in states of walking on an even surface, climbing stairs, coming down the stairs, sleeping, sitting and climbing a steep road, and the gathered data was analyzed using statistical tests.
Based on the results of this study, 2 and 3 weeks after the treatment, the effect of CM Topical Lotion on reduction of pain while walking on an even surface had significant difference compared to the placebo (p<0.01). Also, CM Topical Lotion had relatively better effect compared to mint lotion on the intensity of pain while walking on an even surface and sitting (however, the difference was not statistically significant). Two weeks after the commencement of the treatment, the intensity of pain while sleeping reduced significantly in the CM Topical Lotion group compared to mint lotion group and the placebo group (p<0.01).